Jack and jiggle jack



Feb. 11,1941 AR iER 2,4155% JACK AND JIGGLE JACK Filed April 8, 1945 ,7Sheets-Sheet l IHHIIIIIHII M. GARANCHER JACKJWD JIGGLE'JACK I FiledApril s, 1943 Feb. 11, 1947.

7 Sheets-Sheet 5 .l |||||\|HHH v Feb. 13 M? v .MQGARANCHER ma ma JACKAND JIGGLE JACK Filed April 8, 1943 7 Sheets-$heet 4 mrws Feb. 11, 1947.r M. GARANCHER 2,415,684

JACK AND JIGGLE JACK Filed April 8, 1943 v 7 Sheets-Sheet 5 Feb. 11,1947. R 2,415,684

JACK AND JIGGLE JACK Filed April 8, 1945' 7 Sheets-Sheet 7 7/1651gwpajnfilr 1 W, W 6% Patented Feb. 11, 1947 JACK AND JIGGLE JACK MarcelGarancher, Chicago, 111., assignor to Stewart-Warner Corporation,Chicago, Ill., a corporation of Virginia Application April 8, 1943,Serial No. 482,242

9 Claims.

This invention relates to an air operated jack and jiggle jack for usewith vehicles.

One object of this invention is to provide a jack which will collapse tosmall dimensions and which can be used wherever air pressure isavailable for lifting the vehicle, or a part thereof, and holding it inits lifted position, or for lifting and lowering the chassis of thevehicle repeatedly and automatically for the purpose of freeing up thespring shackle bearings and for assisting in working grease into suchbearings.

Another object of my invention is to provide a jack which can be readilyadjusted by hand to a position to contact with the part of the vehicleto be lifted and thereafter be operated by air pressure to raise andlower the vehicle part with which the jack has been connected.

: Another object of my invention is to provide means for causing thejack to jiggle with a stroke less than that of which the jack is capablewhen used only for hoisting.

Another object of my invention is to provide a jack'in which the movableparts are suitably protected against dirt which frequently falls uponthe jack from the vehicle.

Still other objects and features of my invention will appear from thefollowing specification and drawings, in which like parts are designatedby like characters throughout the several views.

My invention is illustrated in the accompanying drawings, in which Fig.1 is a plan view of the top of the jack;

Fig. 2 is a vertical sectional view showing the jack in its fullycollapsed condition;

Fig. 3 is a fragmentary section taken on the line 33 of Fig. 1;

Fig. 4 is a vertical sectional view showing the two jack extensionmembers adjusted into their raised positions;

Fig. 5 is a horizontal sectional view taken on the line 55 of Fi 2;

Fig. 6 is a horizontal section taken on the line |i6 of Fig. 2;

Fig. '7 is a horizontal section taken on the line of Fig. 2;

Fig. 8 is a horizontal section taken on the line 88 of Fig. 2;

Fig. 9 is a horizontal section taken on the line 9-9 of Fig. 2;

v Fig. 10 is an enlarged fragmentary vertical section taken through thecenter of the valve mechanism for the jack;

Fig. 11 is a horizontal section taken on the line of Fig. 2;

Fig. 12 is a vertical section taken on the line |2|2 of Figs. 10 and 11;

Fig. 13 is a vertical section taken on the line |3--|3 of Fig. 10;

Fig. 14 is a horizontal section taken on the line |4-|4 of Fig. 10;

Fig. 15 is a vertical section taken on the line |5|5 of Fig. 10;

Fig. 16 is a horizontal section taken on the line Iii-l6 of Fig. 10; and

Fig. 1'7 is a fragmentary vertical section of the 'jackshowing the slidevalve in the position in drical housing 2| at the top of which a guidering 22 is mounted and held in place partly within and partly upon theupper end of the cylindri- Cal ho si 2| by means of a pair of arcuateclamps 24 and 25 drawn together about the periphery of the cylinder 2|and guide ring '22 by means of bolts 26 and 21. The cylindrical housing2| is provided with a groove 29 near its upper end, into whichcorrespondingly shaped portions of .the clamps 24 and 25 project, andthe guide ring 22 is provided with a shoulder 30, above which portionsof the clamp members 24 and 25 abut, thus holding the guide ring 22 andthe cylindrical housing 2| firmly together against a very high pressure,which may be applied to the under side of the ring when the jack is inits uppermost position under the influence of high air pressure. Apartition 3| extends across the cylinder 2 I and is suitably welded inplace to form the lower cylinder head.

The piston for raising the jack comprises a circular disc 33, anabutting cup washer 34, a spring cup washer expander 35 and a cup shapedmetallic protector and stop member 36, all held together by means of ahollow nut 31 threaded into the central opening through the plate 33 andhaving a shoulder 38 which clamps the metallic cup member 36, the sprinexpander 35 and the cup washer 34 firmly together in the order named onthe bottom of the circular piston disc 33.

A cylindrical piston rod 40 of a diameter to provide a working fitwithin the guide ring 22 is secured by means of a plurality of screws 4|to the upper face of the circular piston disc 33, the diameter of thepiston rod 40 being somewhat less. than the internal diameter of thecylindrical housing 2!. Suitably welded, or otherwise 35 and 35.

. A ring 46 is secured within the upper end of,

the cylindrical piston rod 49 by a press fit against a shoulder 41formed on the inner wall 'ofthe cylindrical piston rod 40. The openingthrough ring 46 has a greater diameter inone direction than it has inthe direction at'90 degrees'thereto'; as shown in Fig. 9.

Extending through the opening? in the ri'ngf lliis a lifting member 48having wings 49 and 59 registering with the elongated portions of theopening through the ring 46. The lifting memh'r 48 is i'n ole-rein 'o'faslel/E the-ifoot-"M-of which rests upon the upper surface- 6f;the-piston plate 33.- The= foot*of-' the-sleeve 48 'is enlarged to thediameter of the inside of the cylindrical piston 'rdd iil. The-sleeve 48fisalso provided with a second set of wings 52 and '53,-sh"owrrin crossseenen' in Fig. 8; and looated subst'antially'mid way between the upperpair of wings 49 and 50 and the'fdottl "attire-bottom'ofthe sleeve 48.

The upper portion of the lifting-sleeve 48 1s internally threaded at 55to receive a screw-56 carrying altits top-e rvolvable sn'o'e- 58- havinga uewnw erdi projecting" stem 59 rotat ably mounted-within thecylindrica interior of the screw 56. The shore 58 is provided with aplurality; preferably four, of sm'all projectiohs 60 to prvnt"th'e'sho'e from slipping: olT ofa pertihnbf "a vehicle against" whichit is pressin for crapper-jigging purposes. The stem 59 is'pr'ev'nted'from making acomplete revollition within "the 'screw- 55 by rrians offa" set screw 6! extends into a groove tz (Fig. 5) which is chi; onlypart way aroufid-tliestem '59. A ball as is pressed by a s ri g 61againstthe inner serraee ofthe cylindrical screwifi 't'oprevnt a tooready-rotational movement of the stem 'li9 within thescrwifi.

A "metallic disc 69 (Fig. 6) is p'rovided with a toiigueflil extendmgirito'a'keyway H cut lengthwispf the lifting sleeve-4a. The periphery ofthe rri'et'allic disc '69 rests Io'oslyupon a shoulder l2g formed 'atthetop' of the inner 'wallfofithe cylindrical piston rod lil;the'metallicidisc '69-'be= irrgirot'atablelwith 'the lifting sleeve- 48and rotatablewith'in" the cylindrical piston rod 405 An operatordesiring to" place theiack under apart to be lifted rotates the shoe 58by means of the projections-ffiile-thus raising the screw 56 withinthe'lifting'sleeve18 until thersl'ioe'fifi contacts the 'part' of thevehicle to be raised, or else until the'screw 560011'1'83 toth'e end ofits movement. If at this time the'-shoe-58' is still a considerabledistance' below the partof'the ve hicle on: which the raising-force isto be applied, theshoe"58 is'lifted byi han'du'ntil either the upperpairof wings and 50 is :raised above the upper surface of the ring 48,or if this is not high enough, then-until the lower pair of wings 52 and53 is raised above the upper surface of the ring 46.

At on'e' of the two before" mentioned ralse'd p'ositions of the liftinsleeve 48'th'e operator rotates tlie sleeve 48through90 degrees topermit oneof the setSOf wings; eithr lflarid 50" 01*52 and 53,110 restin depressrenssaer the same shape 4 as the wings formed in the oppositesolid portions of the ring 46. The piston is now raised by theapplication of compressed air between the cup washer 34 and the cylinderhead 3!, the lifting sleeve 48 being raised either by reason of the factthat its foot 5| rests upon the upper surface of the piston disc 33, or;by reason of the fact that one or the other of itspairs of wings 49 and5B, or 52 and 53, rests upon the .solid portions of the rin 48, whichrises with the piston rod 40.

V In all of the various positions of elevation of the parts of the jackthe screw 55 is held in axial alignment with the cylinder 2i by thethreads 15;,

"in axial alignment with the cylinder 2| by its in the li'fti'rig'sle'v'e48. The lifting sleeve is held circumferential foot 5!, and bythe close fit of its upper portion within the opening through the ringi'fi; The piston rod is held in axial alignment with the cylinder 2| bymeans of the cupped plate 33; which contacts "the inner wall or thecylinder 2| at a low I point, and the" guide ring 22,- whichcoiitactsthe' piston rod 40 at a point always=somewhat remote-fromthe'point of contactof-themetalliccuptfi within the cylinder wall;

Provision in: the form of'on'e'or more grease nipples 1'3 communicatingwith a: circumferential' gre'ase passage 74 on the inner surface-of theguide ring 22 facilitates lubrication of the working surfaces of theguide'ring 22 and'the cylindrical piston'rod' lfll The' lifting strokeof thej'ack is the distance between the'upper surface oftheoircularplate- 33 andth'e lower surface of the" guide ring'22}Because-mypneuznatic jackds arranged'forautomatic operation toraiseahdlower'the vehicle periodically, or'fo'rmanu'al operation toraise andlower the Vehicle at will, certain valve mechanisms are provi'dedfora'dmittingand relieving the air in accordance with the' desiredoperation.

Thaauto'matic valve mechanism as shownin Figs. I0, '11,:l-21andv1-7comprises a; mechanism to be-here'inafter'fully described for moving aslide valve member 'l'i from/its lower position, shown in Fig.'10, toits upper-position; shown in'Fig. 17. This slidevalve member if includesa rectangular block with a; depression 18 milled into one side forcompleting or cutting err communicationbetween the passageways '19 and'86 drilled: through the polished faced, generally cylindricalplug 9|.The opposite sideof 'the'slide' valvem'ember 11' is provided witha-milled slot 82 out with" the axisof the miller in 'a pla'ne' at rightangles tothe plane of theaxis of theunill'er with which-the depression18 is cut. The purpose of the'depress'ionfl is-to forman' abutmentagainst a circumferential ridge lit-formed between two circumferential:valleys 85 and 86 in the reciprocable operating'sleeve 88 (Figs. 11and-:12) to'prevent-the'valve block' H from moving laterally acrossoperating sleeve-88. Balls:89-and"90-pressed' into -thevalleys BE-or 86by springs 92 and 93 serve to holdthereciprocableoperating sleeve88,-and consequently the valve block ll, in either their upper or lowerpositions. Theinterior of-thereciprocable sleeve 88 is provided at itscehterwith an integratinwardly projecting ring 94 forming seats for thesprings 95'an'd 96. The ends 'ofthe springs 95 and 96, remote from thering 94, abut shoulders 91 and 98, respectively, carried by an operatingrod99.

The springs 95 and were dfsu'ch' length that theyare continuouslyslightly. compressedb'etween the shoulders 91 and98 and'aire of suchstrength that when the operating rod 99 is moved downwardly, as will behereinafter described, the reciprocable sleeve 88 will move with a snapmovement from its upper position, in which the balls 89' and 90 rest inthe valley 86, to its lower position in which the balls 89 and 99 restin the The movement of the operating rod 99 from one position to theother will be most readily understood by reference to Figs. 2 and 17.The operating rod 99 extends upwardly through a packing gland I and intothe spring housing 43 which is movable with the piston members of thejack. The upper end of the operating rod '99 is reduced in sizeproviding a shoulder I02, upon which a movable abutment I03 and a springI04 normally rest. The upper end of the spring I04 abuts the cap 44 atthe upper end of the spring housing. The extreme upper end of the rod 99carries a nut I of a size which will not pass through the opening in themovable spring abutment I03. 1

As the jack piston rises the spring I04 gradually elongates until theabutment I03 rests upon the circumferential stop I01 formed within theclamping nut 3?. Throughout that portion of the movement of the jackpiston upwardly in advance of the contact of the movable spring abutmentI03 with the stop I01, the spring I04, by its downward pressure on theoperating rod 99, holds the reciprocable sleeve 88 in its lowerposition.

- When the jack piston has risen substantially to its uppermostposition, the nut I95 on the upper end of the operating rod 99encounters the upper surface of the movable spring abutment I03 pullingupwardly on the rod 99 and compressing the spring 96 until its pressureso far overbalances spring 95 that the reciprocable sleeve 89' snapsfrom its lower position to its upper position. Conversely, as the jackpiston moves to its lower position, the shoulder I62 engages the underside of the spring pressed movable abutment I03 producing a downwardmovement of the operating rod 99, which compresses the spring 95 andelongates the spring 96 causing the reciprocable sleeve 88 to snap toits lower position. The automatic reciprocation of the piston takesplace, therefore, as hereinafter described, between the top of thestroke of the piston and that partially contracted position in which theshoulder I02 contacts the movable abutment I03. The pressure of springI94 is sufficient to trip the valve rod 99 but is insufficient toprevent the jack from fully retracting under its own weight when the airpressure is manually cut off and the relief valve is manually opened.

The reason for preventing the jack from moving to its fully contractedposition during jiggling is that the jack must be placed by hand underthe part to be jiggled and, therefore, will not always be tight betweenthe ground and the part to be jiggled before the air is applied. If thejack returned to normal at the lower end of each jiggle stroke, it wouldbe likely to work itself out from under the part being jiggled.

The passageways through which the compressed air is admitted to andrelieved from the space beneath the cup washer 34 of the jack piston aremost readily traced in Figs. to 16, in-

clusive. Air under pressureis'fed 'to'the lack through conduit IIO. Aconical valve III operating on a seat II2 by means of a hand wheel II3admits high pressure air into the pipe II5 communicating with the valvechamber II6. A double seated valve H8 in the chamber I29; provided withsealing rings I I9 and I20, is moved between its seats I2I and I22 bymeans of a shank I23 threaded in a packing gland nut I24 and provided atits outer end with a hand wheel I25. The function of the valve H8 is tochange the jack from its mere hoisting function to its jigglingfunction; The valve H8 is shown in" Figs. 10 and 11 in the position forthe hoisting function.

When the valve H8 is in its hoisting position, compressed air from thevalve chamber I.I6 passes through drilled conduit I21 and lateralconduits I28 to the chamber I29 in which the valve II 8 operates. Fromthe chamber I29 the air passes through the diagonally drilled conduitI30, shown in phantom in Figs. 11, 12, 13 and 14,- to the position inwhich this conduit communicates with the horizontal conduit I3 I', fromwhich, the air passes upwardly through conduit I32 into the space belowthe cup piston 34, as most clearly illustrated in Fig. 12. The airpassing through these passages causes the piston to rise until'the airis cut off by the rotation of the hand wheel I I3, or alternatively,until the jack piston reaches the top of its stroke, at which point theupper surface of the outer portion of the circular plate 33 contacts theunder surface of the guide ring 22. When the lowering of the jack isdesired, a valve I35 normally in contact with a seat I36 is opened bymeans ofthe relief hand wheel'I3I: permitting the air to escape from theunder side of the piston by reverse flow through the same passagesthrough which the air was admitted, thence through the diagonallydrilled conduit I30, past the valve seat and valve I36 and I35, and toatmosphere through the drilled conduit I39. By moving the valve I35 onlyslightly from the seat I36 the lowering of the jack may be made verygradual, whereas by moving the valve I35 a substantial distance from itsseat I36 the jack will be caused to lower quickly. I

When it is desired that the jack shall operate to jiggle a vehicle, thehand wheel I25 is rotated in a counter-clockwise direction until thesealing ring I20 presses against its seat I22 closing at this point thecommunication heretofore describedfor the passage of compresed air intothe compartment I29 in which the valve II8 op-. erates. With the valveH8 in its jiggling position, compressed air is admitted by the rotation:of the hand wheel I I3 and the consequent movement of the valve III fromits seat H2. The air thus admitted to the valve chamber II6 now passesthrough drilled conduit I9, thence through conduits I30, I3I and I32 tothe under side of the piston.

When the jack piston is raised to the top of its stroke, thereciprocable sleeve 88 and its associated valve block 11 are moved totheir upper po-' sition by means hereinbefore described, thus closingtheentrance to the drilled conduit I9 and connecting that conduit throughthe depression I8 in the valve block 17 with conduit 80, throughwhich'the air now passes from the cylinder to the space within the boreof plug I42, into which is threaded a screw I43 from which the apex ofits thread has been removed or omitted, as shown at I44, Fig. 10.

By adjusting the screw I43 inwardly or 'outwardly, the length of thetriangular ,passageway between the flat portions of, the threads :01:the screw I43 anditheapex "of the threads 'inzthe plug M2 maybe:c-hanged'to'change the resistance or the flow of :air out ofthecylinder; By this means the speed .of' lowering of the jack cylinder'maybe regulated, whereas the speed of rise of the jack cylinder will,beiregulated by the adjustment of the hand wheel H3.

When the piston reaches a predetermined point 'in its downward movement,the sleeve 88 and valve block Tl are moved downwardly by themean's abovedescribed forputting the. bore 79 again into communication with thechamber 6 as shown in Fig. 10 for enabling the compressed air again toraise the piston. This alternate upward and downward movement of thepiston continues normally -until the valve H8 is again moved toward-theleft to the position as shown in Fig. 10.

It will be understoodithat the diameter of the cylinder and housing 2|will be'selectedin accordance with the weight of the vehicle to belifted and the 'air pressure available; Inasmuch as my jack is intendedprimarily for use inautomobile service stations, the air pressureavailable will ordinarily be that provided for the inflation ofautomobile tires, usually held at about 100 pounds per squareinchin theservice tank.

While I have shown and described particular embodiments of'my invention,it will be apparent tothose skilled in the art that numerousmodifications and variations may be made without departing from theunderlying principles of the invention. vI :thereforedesire, by thefollowing claims, to include within the scope of the invention .all suchmodifications and variations by which substantially the results thereofmay be obtained byzsubstantiahy the same or equivalent means.

.Having thus descr'ibedrny invention, -.what-I claim as new anddesiretosecure by Letters Patent of the United States is:

In a jack comprisinga cylinder with a pneumatica-lly operated pistontherein, an air induction passageway leadingtosaid cylinder, 2. pressuresupply valve and a: pressure release :va'lve controlling said'passagewayand both operable at will, together with a manually operable 'valvehaving a chamber included vin :said'passageway, a pair of seats withwhich said valve :is alternatively .engageabl'e, and an automatic valveactuatedby the piston to cause said piston to rise and fallperiodically, the engagement ofzsaid manually. operable valve with oneof its -.seats serving to close passages vleadingfrom the valve chamberdirectly to said cylinder and :to.=open passages leading :irom saidchamberato the :automatic valve 'to causes-said periodic movements ofthe: piston, and the engagement of .sai'dtvalye with the other of saidseatssiserving to cut .ofi communication between said valve chamberzgandthe automatic-waive andto openifthefpassages leading directly'to :saidcylinder for 'placingth'e piston iu'nder control of said pressure supplyand pressure release valves.

2. In a jack comprisinga cylinder with a pneumatically operated pistontherein, an airunductionpassagewayleading to said cylinder, :8. pressuresupply valve and a pressurerelease valve controlling said passageway'and'both operable at will, together with a-manually operablewalve having achamber :included 'in said passageway, a pair of seats withwhichsaidnnanually operablewalve risralternaltively engageable, and anautomatic valve actuated by the. piston within a; limited portion of itsfull range of :movementin-,the cylinder to .cause said piston'rto riseand fall periodically withinsuch limited :range, the en gagement ofsaid; manually operable valv with one of said seats serving toclosepassages leading fromzthe valve chamber directly to said cylinderand to open passages leading from said chamber to the -automatic valveto cause said -periodic movements. of the piston, and the engascmcntofsaid valve with the other of said seats vin cut ofi communicationbetween the valve-chamberand the automatic valve and to open thepassages leading directly to said cylinder for placing said piston-undercontrol of said pressure supply and pressure release valves.

3. In a; jack, thecombination ofapiston movable vertically in acylinder,means providing' w chambers, means for feeding airunder pressure tooneof said chambers, means connecting the other. of said chambers withsaid cylinder underneath said piston, two separate connections -be-.tween :said two chambers, manually operable valve means for closingeither ofsaid separateyconnections while leaving theotheropen, othervalve means adapted in one operative position r cluse one of saidconnections and to :connectsaid other chamber with-an exhaust opening,and automatically operated means for moving ,saidlastnamed valve means.alternately into and out of said on operative position.

4. In-a jack, the combination ofapiston movable vertically in a.cylinder, means providing two chambers, means for feeding air underpressure to, One of said chambers, means connecting the other of saidchambers with saidcylinderv underneath said piston, two separateconnectionsbetween said two chambers, manually operable valve means insaid other chamber ,for closing either of said separate connectionswhile leaving the other open,,o,ther valve means in said, one chamberadapted in one operative position. to close one-of said separateconnections and to connect said other chamber with an exhaust opening,and; automatically operated means for moving said last named valvemeansalternately-into and out of said one operative position.

5,. ,In a jack, thecombination of a .pistonmovable vertically in acylinder, meansproviding two chambers, means for feeding air underpressure to. one. of said chambers, means connecting the other of saidchambers with said cylinder :underneath said ,"piston, two separateconnections :between said two chambers, manually operable valve means,for closing either of said connections while leavingthe other open,other valve means adapted in onecoperativelposition to close one of saidseparate connections and to connect said other chamber withan exhaustopening, and meansactuated by the vertical movements .of said piston inopposite directions for moving/said last namcd valver means alternatelyinto and out of said one operativeposition.

46. In a .jack, a pneumatically operated Lhollow piston, -a-.valveoperating rod extending :into the hollow portion 'of the piston a springsurrounding the rod:and;abutting at one .end. against an abutmentifixedwith respect to the.- piston, 13in abutment:movable with respect to .thepiston against which the other end of the spring abuts, ;a :projectioncarried'jby the piston :upon .Whi'ChASflld movable abutment rests when'the .spring:is in its condition of :g-reatestcxpansion, a :shoulderon-rtheryalve operating :rod for-engagement-mth the movable abutment-formoving. the valve operating rod downwardly when the piston movesdownwardly to an intermediate position of its stroke, the said valveoperating rod being provided with an enlargement for engagement with theupper side of said movable abutment when the piston rises to near thetop of its stroke whereby the valve operating rod is moved upwardly, theshoulder on the valve operating rod serving to move the movable abutmentrelative to the piston when the piston is lowered beyond theintermediate position at which the shoulder on the piston rod engagesthe movable abutment.

7. In a jack, a piston for movement under air pressure, a cylinder inwhich said piston may be moved between upper and lower positions by themanual relief of the air pressure under said piston, an automatic valveoperating rod, an abutment movable with the piston for'engagement withsaid valve operating rod to move the rod in one direction when thepiston approaches the top of its stroke and to move the rod in the otherdirection when the piston arrives at an intermediate position in itsstroke, the said automatic valve serving to admit the release airpressure from the under side of the said piston whereby the piston willreciprocate automatically between two positions less than the completestroke of the piston, a spring carried by the piston and acting upOnsaid movable abutment to move the automatic valve operating rod in oneof its directions, the lowering of the piston below the intermediateposition in which the movable abutment engages the automatic valveoperating rod serving to compress the spring.

8. In a jiggle jack, a pneumatically operated piston, a slide valve foralternately admitting and releasing air to and from the face of saidpiston, a pair of opposed springs pressing in opposite directions uponsaid slide valve in the line of its movement, a part of said slide valveprovided with a pair of depressions, a ball which is spring pressed intoone of said depressions when the slide valve is in one extreme positionand into the other of said depressions when the slide valve is in itsother extreme position, and operating means comprising a third springmoved by the piston upon a stroke in one direction for applying pressureon one of said opposed springs to cause the slide valve to move in onedirection and moved upon a stroke in the other direction for applyingpressure on the other of said opposed springs to cause the slide valveto move in the opposite direction.

In a jiggle jack, 3, pneumatically operated piston, a slide valve foralternately admitting and releasing air to and from the face of saidpiston, a pair of opposed springs pressing in opposite directions upon apart of said slide valve in the line of its movement, a part of saidslide valve being provided with two vertically spaced pairs ofoppositely disposed depressions, a pair of balls which are springpressed toward one another into said depressions on the opposite sidesofsaid part of said slide valve when the slide valve is in one extremeposition and into other of said depressions when the slide valve is inits other extreme position, and an operating member moved by the pistonat an intermediate point in its downward stroke for applying pressure onone of said opposed springs to cause the slide valve to move in onedirection and moved at about the end of the upward stroke of the pistonfor applying pressure on the other of said springs to cause the slidevalve to move in the opposite direction, the said opposed springspermitting the slide valve to move from one position to the other with asnap movement.

MARCEL GARANCHER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

